Eyebrows were raised earlier this year when the PBS Masterpiece miniseries Downton Abbey announced it would be entering for Emmy consideration this year as a drama series, after its surprising domination of the longform race in 2011 with six wins. The conventional wisdom was that it couldn’t pull a repeat performance this time against such cable stalwarts as Mad Men, Breaking Bad and Boardwalk Empire and hot newcomer Homeland. But the British period drama exceeded expectations this morning, and then some. After earning 11 noms a year ago, it hauled in a whopping 16 this time, including honors for top drama series, lead actor Hugh Bonneville, lead actress Michelle Dockery, supporting actors Brendan Coyle and Jim Carter, and supporting actresses Maggie Smith (who won last year) and Joanne Froggatt. That’s in addition to writing and directing nominations — the writing for creator Julian Fellowes. The six nominated performers tied for most among drama series with CBS’ The Good Wife, and the 16 total honors was second only to Mad Men’s 17 among all series. The British invasion this morning also included a surprising 13 nods for the Masterpiece entry Sherlock: A Scandal in Belgravia.

To find the last time a British-produced program did this well in the drama series category, one must go back to the mid-1970s when the Masterpiece Theatre production Upstairs, Downstairs won the Emmy for top drama in 1974, ’75 and ’77 against the likes of The Waltons, Kojak, Streets Of San Francisco, Police Story and Baretta. Meanwhile, the only other show in recent years to shift from miniseries to dramas series at the Emmys was USA Network’s The Starter Wife, which started off as a mini, in 2007-08. The reason for the Downton switch, according to Rebecca Eaton, exec producer for PBS’ Masterpiece and Downton Abbey, was the opportunity to test a show that had grown into a worldwide phenomenon in the Emmy equivalent of the major leagues. “We won against some very stiff competition last year from HBO,” Eaton told Deadline. “But in American TV, the drama series track clearly is the faster track. It’ll be interesting now to go toe-to-toe with those very different shows and see how we do.” Added Gareth Neame, managing director of Carnival Films and executive producer of Downton: “We were delighted with how we did last year as a miniseries, but we also knew with a second season that we would be moving into the drama series category, which is much more challenging. Fortunately, the writing and acting have been extraordinary for Season 2”.

Indeed, last year Downton Abbey had to beat HBO’s Mildred Pierce, Too Big To Fail and Cinema Verite. This time, it’ll have its hands full in the lead drama lineup competing with AMC’s Mad Men and Breaking Bad, HBO’s Game Of Thrones and Boardwalk Empire, and the Showtime freshman Homeland. In hindsight, Downton’s strong showing this morning perhaps wasn’t entirely shocking: It has the Masterpiece pedigree that’s proven to be like catnip for Emmy voters. And its big performance at the nominations allows Academy members to feel downright worldly that they’re so generous to a UK co-production (Britain’s Carnival Films, acquired by NBCUniversal in 2008, and pubcaster WGBH/Boston). On the other hand, it’s the kind of show that’s usually honored in the longform lineup rather than challenging the big-shots of cable. And clearly, the show’s nomination dominance knocked Good Wife from the drama series nominee ranks for the first time in its three-year existence. Will it have enough juice to keep Mad Men from earning its fifth Emmy in a row for Outstanding Drama? Not likely. But it tosses a new wrinkle into the race that previously lacked. It also leaves the category entirely free of a commercial network series for the first time ever.